The invention relates to an irregular-motion mechanism consisting of two series-connected double cranks of which the driving link of the first double crank and the driven link of the second double crank are centrally mounted and the driven link of the first double crank is rigidly coupled to the driving link of the second double crank.
An irregular-motion mechanism of this type offers the advantage over an irregular-motion mechanism whose drive comprises only a single double crank that the driving and driven members remain centrally disposed regardless of the degree of irregularity of motion for which the mechanism is set. A further advantage of the dual double crank over the single double crank is that it permits the mechanism to be set for higher degrees of irregularity. A drawback, on the other hand, is the high loading of the crank with high degrees of irregularity.